A Review on Agro-Waste-Derived Carbon Dots as Multifunctional Nanofillers in Biopolymer Films: A Sustainable Strategy for Active Packaging and Shelf Life Extension of Seafood

Seafood, rich in nutrients, undergoes rapid quality deterioration, primarily due to microbial activity and lipid oxidation. Conventional petroleum-based packaging is widely used for seafood but lacks the ability to retard spoilage. Carbon dots (CDs), which are nanosized, act as multifunctional additives that can be incorporated into biopolymer films to prepare active, biodegradable packaging. CDs are produced through green synthesis methods using various agro-byproducts, including fruit peels, leaves, and rhizomes, thus aligning well with circular economy principles. CDs have antioxidant and antimicrobial activities, as well as UV barrier properties. CDs from different sources show varying bioactivities and properties. The bioactivities of CDs are enhanced by doping with compounds such as polyphenols and amino acids. When CDs are applied to biopolymer matrices such as chitosan and gelatin, the increases in mechanical strength, water vapor barrier properties, thermal stability, and ultraviolet light-blocking ability can be achieved. Recent investigations into the performance of films containing CDs from different sources for the shelf life extension of various seafood are revisited. The limited commercial implementation, particularly of large-scale synthesis, is addressed. The migration behavior and toxicological profiles are also elucidated. Overall, this review highlights agro-waste-derived CDs as a potential nanomaterial for developing next-generation active packaging systems for seafood preservation and environmental sustainability.